Coverage.py includes a C extension for speed. It is strongly recommended to use
this extension: it is much faster, and is needed to support a number of
coverage.py features. Most of the time, the C extension will be installed
without any special action on your part.

If you are installing on Linux, you may need to install the python-dev and gcc
support files before installing coverage via pip. The exact commands depend on
which package manager you use, which Python version you are using, and the
names of the packages for your distribution. For example:

For Windows, kits are provided on the PyPI page for different versions of
Python and different CPU architectures. These kits require that setuptools
be installed as a pre-requisite, but otherwise are self-contained. They have
the C extension pre-compiled so there’s no need to worry about compilers.